I'd suggest dropping the HP 1340A altogether. Instead, check some of the Eurorack LCD displays that can be mounted as a normal module. This would give you a smaller screen, but since this also means a smaller objective for the feedback cam, you can then use a smaller surveillance-type camera and mount this closer to the front panel for better ergonomics. Go with something bigger for your external mix monitor (again, LCD is better, especially if you want portability here, since a CRT monitor won't like being hauled around all that much), and then consider something like a Tektronix 1740A to monitor your image vectoring for diagnostics.